Abstract
This thesis covers three works: control Modulation instability (MI) by partial coherent light, control MI by background to signal beam intensity ratio, and control MI by periodically driving fi eld. The first work introduces the phase diagram of biased voltage versus coherence length. MI1, MI1/MI2, MI2, Transverse Instability (TI), Optical turbulence (OT) states can be observed. MI1/MI2 mixed state can be explained by unisotropic nonlinear indexes and the transition boundaries of plain wave to MI1, MI1 to MI2 phases can be depicted on the phase diagram. The second work explains the MI suppression behavior in high intensity region which reveals saturable type refractive index to light intensity response. One can control the clear MI pattern range of signal light intensity via signal to background intensity ratio. The third work controls MI variation range using external periodic driving field with fast charge carriers dynamics assumed. MI with periodic driving could be a promising tool for measuring perturbation frequency when non-intuitive resonance peak is observed.